“What our study shows is that even a relatively brief, low-level exposure to oil harms the swimming capabilities of mahi-mahi, and likely other large pelagic fish, during the early life stages,” Edward Mager, RSMAS postdoctoral associate and lead author of the study said in a news release. “If you harm a fish’s ability to swim you also harm its ability to perform actions that are critical for survival, such as catching prey and evading predation.”

Researchers exposed larvae and juvenile mahi-mahi to Deepwater Horizon crude oil that was collected from the spill on July 29, 2010. One group was exposed to oil-spill conditions for 48 hours during the larval stage and then raised in clean water to the juvenile stage; the other group was raised in clean seawater during the larval stage and then exposed to oil-spill conditions for 24 hours.

They found that the group exposed for 48 hours experienced a 37% decrease in swimming velocity, while the 24-hour group experienced a 22% decrease in swimming velocity.

These results highlight potential problems for mahi-mahi because fertilized eggs float near the surface of the northern Gulf of Mexico, an area affected by the 2010 oil spill, and are believed to stay there during the early stages development. Oil exposure during these stages may decrease fish survival and lead to a decline in fish population levels for a period of time.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of MarineScienceToday.com. She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science. She is also a PADI diver and dog lover. More from this author.

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